Abstract: The object of this invention is a suspension of metal nanoparticles with a mean size of between 1 and 20 nanometers, in at least one non-aqueous ionic liquid, whereby said suspension also contains at least one nitrogen-containing ligand, in which said metal nanoparticles comprise at least one transition metal in the zero valence state that is selected from among rhodium, ruthenium, iridium, nickel, and platinum by themselves or in a mixture and in which said nitrogen-containing ligand is selected from the group that is formed by the linear compounds that comprise at least one nitrogen atom, whereby the non-aromatic cyclic compounds comprise at least one nitrogen atom, the non-condensed aromatic compounds comprise at least one nitrogen atom, the condensed aromatic compounds comprise at least one group of two aromatic cycles that are condensed two by two, and at least one nitrogen atom, whereby the condensed aromatic compounds comprise at least 3 aromatic cycles and 1 nitrogen atom, and whereby the condensed ar

Abstract: This invention describes a process for hydrogenation of an aromatic feedstock that as a catalytic composition uses a suspension of metal nanoparticles of a mean size of between 1 and 20 nanometers in at least one non-aqueous ionic liquid, whereby said suspension also contains at least one nitrogen-containing ligand, in which said metal nanoparticles comprise a transition metal in the zero-valence state, whereby the transition metal is selected from the groups 8, 9, 10 and 11 of the periodic table and in which said nitrogen-containing ligand comprises 1 to n nitrogen atoms, whereby n is an integer of between 1 and 20.